Two very physiologically important oxidases, cytochrome oxidase and cytochrome P-450 and associated redox proteins are being sequenced with the goals of determining their structures for subsequent structure-function investigations, for structure determination by X-ray crystallography, and for numerous other purposes. The oxidases and related redox proteins are membrane proteins and new methods are being developed for sequence determination of these hydrophobic proteins. In addition, new sequence techniques, in general, are being developed. It is important that this development in microsequencing of hydophobic membrane takes place since many of the remaining biologically important proteins fall into this category. The sequence and structure determination of the cytochrome oxidase, which contains 7 subunits and the structure-function studies proposed will determine greatly the future direction of cytochrome oxidase research and also may shed light on the mechanism of ATP production during the normal operation of the mitochondrial electron transport system. The structure determination of the cytochrome P-450, a mixed function oxidase, is of great importance since it is involved in the metabolism of drugs, environmental pollutants and carcinogens. Therefore, the key for many future investigations with these physiologically important enzymes requires a detailed knowledge of their structures, and the sequence studies must first be completed. In the case of the cytochrome P-450 from Pseudomonas putida, structure determination by crystal X-ray diffraction procedure is occuring simultaneously in the laboratory of Dr. Kraut and with whom we are in close contact. Thus, the findings of the proposed research are of great importance to biochemists, pharmacologists, cancer researchers, physical biochemists, ecologists, etc.